Adjustable mechanism for operating electric switches



July 12, 1955 H. P. FULLERTON ADJUSTABLE MECHANISM FOR OPERATINGELECTRIC SWITCHES 5 Sheets-Sheet 1 Filed May 9, 1952 m t r wk d mt mm me a H.

His AUb oTneg July 12, 1955 H. P. FULLERTON ADJUSTABLE MECHANISM FOROPERATING ELECTRIC SWITCHES 5 Sheets-Sheet 2 Filed May 9, 1952 lnv enterHerbert P. Fullerton b8 W KM Q a hv l'lis Attorney.

July 12, 1955 H. P. FULLERTON 2,713,095

ADJUSTABLE MECHANISM FOR OPERATING ELECTRIC SWITCHES Filed May 9, 1952 5Sheets-Sheet 5 f M w 9,2 5 CZ i3 211 1.1. l9

IE1: a2 97 w x /0/ -/6'6 a4 4 LP in ifimm i m I as Mir 4?; -//9 \E] 2%a; /20 m; w; lib my W E Inventor: @Q Herbert P. Fullerton 5 w w 3 y WWWbv ih 2Q, HIS Attorney.

United States Patent 0 ADEU TABLE MECHANISM FUR U-PERATING ELECTR1SWITCHES Herbert P. Fullerton, ipringfield, Pa., assignor to GeneralElectric Company, a corporation of New York Application May 9, 1952,Serial No. 286307 '7 Qlaims. ((Il. 20031) This invention relates tocyclic mechanism for operating electric switches and provides animproved adjustable cyclic mechanism capable of efiecting changes in thedwell or closed time of a sequentially operable switch contacts used inrectifiers or inverters of the mechanically controlled contact type asdistinguished from converters utilizing electric valves.

In rectifiers of the mechanical type, it is well known that any contactcycle adjusting mechanism must be capable of the accurate timing ofalmost infinitesimal continuously successive intervals since thecyclically operated contacts open and close sixty times a second at theordinary alternating current frequency or more than five million timeseach day and that the time during which the contacts of the rectifierare allowed to remain closed during each cycle comprising an opening andclosing operation of the contacts is dependent in part upon themagnitude of current which is being supplied by the rectifier. Thus, ifa mechanical rectifier is operating normally and delivering a certainamount of load current, an increase in the load current may require anincrease in the dwell or closed time of the contacts of the rectifierwith a corresponding decrease in the switch opening time during thecycle. Additionally, it is essential that the dwell or closed time ofthe contacts be substantially the same for all contacts. Sincemanufacture of parts to the required degree of accuracy is not practicaland differences of wear during operation would, in any case, destroysuch initial accuracy, it is found necessary to provide a method foradjusting individually the dwell time of the contacts. Further, whenstarting rectification, it is advantageous to utilize the contacts ofthe rectifier to energize the direct current buses before the final loadcircuit completing operation. Thus, the contact dwell of all contacts ofthe rectifier would be adjusted to zero, all other portions of the buscircuit would be closed, and then the contact dwell would be increasedto that required for normal operation so that rectification could bestarted upon closure of the load circuit breaker.

In certain known mechanical rectifiers, it is necessary to shut down therectifier in order to adjust the dwell time of the individual contactsto accommodate changes due to wear or replacement of contacts.

One object of this invention is to provide improved adjustable cycliccam mechanism having a cam follower assembly including an oscillatingelement provided with an adjustable fulcrum for regulating the dwelltime of the contacts of a mechanical rectifier so as to be capable of adesired adjustment while the rectifier is in operation.

Another object of this invention is to provide an improved mechanicalrectifier which is characterized by a high degree of adaptability so asto accommodate a wide variety of service conditions.

According to the invention a revolving cam member is spaced from arectilinearly movable switch member that is biased to a predeterminedclosed position and cooperates with adjustable thrust means including areciprocating contact operating member biased out of engagement with thecontact member and an oscillatory member interposed between the cammember and the reciprocating member and having the fulcrum of theoscillatory member adjustable to thereby inversely vary the contactopening and closing parts of each revolution of the cam member. Theadjustable oscillatory member may comprise a tapered member disposedtransversely with respect to the direction of operation of thereciprocatory member, and means for adjusting the fulcrum of thetransversely disposed member is provided for shifting the reciprocatingrange of the contact operating member relative to the closed position ofthe switch member. In this way the dwell time of the switch member isregulated for each cycle comprising an opening and closing operation ofthe switch member.

For a better understanding of the invention reference may be had to thefollowing description taken in conjunction with the accompanyingdrawings in which Fig. 1 is a schematic representation of a systemshowing the connections of a schematically represented mechanicalrectifier; Fig. 2 is a perspective external view of a mechanicalrectifier embodying the principles of the invention; Fig. 3 is across-sectional view through the apparatus of Fig. 2 showing one pair ofcontact members together with the adjustable thrust transmitting meanscomprising a principal feature of the invention; Fig. 4 is a front viewpartially in section of a mechanical rectifier embodying an alternativearrangement to that disclosed in Figs. 1, 2, and 3; Fig. 5 is a sideview, also partially in section, of the arrangement shown in Fig. 4, andFig. 6 is a view along the line 6-6 of Fig. 5.

In Fig. 1 a polyphase alternating current circuit comprising conductors1, 2, and 3 supplies energy which is converted to direct current energyby the rectifier cyclically operable contact mechanism and supplied tothe direct current conductors 4 and S. The alternating current circuitcomprising conductors 1, 2, and 3 is connected to the primary 6 of atransformer having a secondary winding 7. The three phase windings ofsecondary winding 7 are respectively connected to the saturable reactors8, 9, and it). These saturable reactors are constructed with a main andone or more control windings wound on a metallic core Thus, the reactors8, 9 and 10 change their impedance as a function of control excitationtogether with the magnitude and polarity of the transformer secondarypotential so that following commutation of current from the outgoing tothe incoming contact the current in the outgoing contact is reduced tosubstantially zero and held there for a relatively long time duringwhich the outgoing contact may be successfully opened. The function ofreactors such as 8, 9, and N as a part of a converter system is morefully described in application Serial Number 172,134, filed July 5,1950, by August Schmidt, Charles H. Titus, and Clodius H. Willis andassigned to the assignee of this invention. The reactors 8, 9, and 10are controlled by the control windings 11, 12, and 13 which areenergized from a source of electric energy having a controlled Waveshape and polarity. The adjustable resistor 14 is used to effectvariations in the magnitude of current flowing through the controlwindings 11, 12, and 13. A reactor 15 may be connected in series withthe windings 11, 12 and 13 so as to smooth the fiow of current throughthese control windings. Each of the reactors is provided with a mainwinding and such windings are designated by the numerals 16, 17, and 18.

Winding 16 is connected to fixed contacts 19 and 20, winding 17 isconnected to the fixed contacts 21 and 22, and winding 18 is connectedto fixed contacts 23 and 24. Negative direct current conductor 4 isconnected to fixed contacts 25, 26, and 2". while positive directcurrent conductor 5 is connected with fixed contacts 28, 29 and 30. Asis indicated in Fig. 1, the space between the abovementioned fixedcontacts may be bridged by the bridging contacts 3136 each of which isrespectively provided with its own biasing spring 3742 so as to bias themovable bridging contact to a predetermined closed position inengagement with the fixed contacts. Each pair of contact sets such as19, 25, 31 and 2t), 28, 32 is controlled as indicated in Fig. l by itsown cyclic contact operating mechanism generally designated by thenumerals 43, 44, and 45. Since these contact operating mechanisms areidentical, the following description will be by reference to theoperating mechanism 43.

Contact operating mechanism 43 utilizes a revolving cam member generallydesignated by the numeral 46 as is shown in both Figs. 2 and 3. The cammember 46 includes a rotatable central shaft member 47 to which iseccentrically secured another element 48. Disposed about the cameccentric 48 is an internal bearing retaining ring 49 upon which aplurality of balls 5i) ride. The operating surface of the cam member 46is in the form of an outer retaining ring 51. Secured to the ring 51 isa radially extending arm 52 on the outer end of which is mounted aroller 5?- movable vertically in a guide slot formed in the fixedsupport structure.

Means not shown in the drawing such as a synchronous type motor isordinarily used to rotate the shaft member 47. Obviously rotation of theshaft member 47 and of the eccentric member 48 which is integrallymovable therewith imparts a cyclic camming action to the ball bearing49, 5t 51 and causes the outer ring 51 to exert a thrust which can beapplied, for example, to the ball followers 54 and 55, so as to exert athrust to the left and to the right. ()uter ring member 51 does notrotate due to the action of the radially extending element 52 and theroller 53 mounted thereon. If desired the elements 52 and 53 may beomitted.

Disposed for respective engagement with the balls 54 and 55 are thethrust means 56 and 57. The thrust means 56 and 57 are of a tapered orwedge shaped construction and, being transversely disposed relative tothe direction of reciprocation to the left and the right of the balls 54and 55, can be used to inversely vary the contact opening and closingparts of each revolution of the cam member as will be more fullyexplained. Cooperatively disposed with respect to the thrust members 56and 57 are the balls 58 and 59 and the reciprocating contact operatingrods 60 and 61 that variably engage respectively with the contactmembers 31 and 32 so as to move those contact members to the opencircuit position against the bias of their respective biasing means 37and 38 during a variable part of each revolution of the cam member 46.

In order to regulate the position of the thrust members 56 and 57 in thevertical direction and thereby to control the contact dwell time inaccordance with this invention, the thrust members 56 and 57 are pivotedrespectively at 62 and 63 to the vertically movable rod members 64 and65 which are biased downwardly by the spring means 66 and 67respectively. Rod 64 is pivotally connected by lost motion means at 63to a pair of cross arms 6? which in turn are pivotally mounted at 70 toa laterally movable pivotal support and at their righthand ends areprovided with openings 76a in which is mounted a rotatable shaft 71 onwhich is mounted an eccentric member 72. Since eccentric member 72 isafiixed to the shaft 71, rotation of shaft '71 will impart verticalmotion to the rod members 64 and 65 as will be obvious from Fig. 1. Asis shown in Fig. l, the rod 65 is pinned at the lost motion pivotalconnection 73 to the pair of transversely disposed operating rods 74which are pivoted at 75 to the fixed support structure and which areprovided with large openings 76 which cooperate with the eccentric 72and its shaft 71 to impart vertical motion to the rod member 65. Thus,it will be seen that rotation of the shaft 71 eifectively imparts up ordown adjusting or positioning motion to the thrust members 56 and 57 andthereby regulates the instant at which the contact members 31 and 32 arerespectively opened and closed during each revolution of the cam member46 so as to regulate the so-called dwell or closed time during eachcycle of opening and closing of these contacts. It will be understoodthat in order to obtain suitable operation the contact operating rods 60and 61 would preferably be biased into engagement with the balls 58 and59 respectively.

Such bias for the rods 66 and 61 is shown at 76a and 77 in Fig. 3, whileguide means 78 and 7 9 are respectively provided for the ball members58, 54, 55 and 59. Also from Fig. 3 it will be seen that suitablesleeve-lilac supports for the thrust rods 64 and 61 are provided in theform of the fixedly mounted elements 80 and 81. It will be understoodthat at least a portion of the thrust rods 60 and 61 should beconstructed of insulating material such as the parts 82 and 83 which arerespectively mounted in the metallic portions 84 and 85 of the thrustrods 60 and 61 respectively.

As shown in Fig. 3, the revolving cam member 46 is in an angularposition to exert a thrust through the ball 55, the tapered thrustelement 57, the ball 59, and the push rod 61, so as to move theinsulated end 83 of the push rod between the fixed switch contactelements 20 and 28 into engagement withthe movable bridging contact 32and thereby move contact 32 from its predetermined circuit closingposition to which it is biased by the spring 38. The distance that thebridging contact 32 is moved away from its circuit closing position willdetermine the length of the contact opening period and will depend uponthe transverse adjustment of the tapered thrust element 57 due toadjustment of fulcrum 63. The farther the contact is moved away from thestationary contacts, the longer the contact opening part of each cyclewill be and vice versa. Correspondingly as cam member 46 revolves to itsdiametrically opposite angular position from that shown in Fig. 3, thepush rod 61 will move out of engagement with the bridging contact 32 alesser or greater distance, thereby respectively decreasing orincreasing the contact closing part of each revolution of the camelement. Thus upon shifting the reciprocating range of the push rod byadjustment of the fulcrum 63 of the oscillatory element 57, the contactopening and closing parts of each revolution of the cam 46 can beinversely varied.

From Fig. 3 it will be understood that the cam member and associatedstructure already described in connection with Figs. 1 and 3 is mountedwithin a metallic support plate member 85 which is supported on theframe members 86 and 87 in any suitable manner. The frame members 86 and87 are secured in position and supported by the supporting frame members88 and 89.

As will be seen from Fig. 3, biasing springs 66 and 67 are retained inposition by the bracket members 90 and 91 which are secured by bolts tothe supporting plate 85.

The bias for springs 37 and 38 is adjustable by means of the adjustingbolts 92 and 93 and parts associated therewith which structures arerespectively mounted in the insulating supports 94 and 95 which aresecured to the frame members by the bolts 96, 97, 98, 99. These boltsare respectively insulated from the current carrying elements by meansof insulating tubes 190-403.

The alternating current buses 16a and 16b which lead from reactor 8 tothe contacts 19 and 20 respectively and the direct current buses 4 and 5and parts associated therewith are insulated from the frame members 86and 87 by insulating means 104 and 105.

The thrust members 56 and 57 are individually adjustable by means of theadjusting nuts 1G6 and 107 and are held in position respectively bytheir locking nuts 108 and 109. Adjusting nuts 106 and 187 cooperatewith transversely disposed members 110 and 111 which respectivelyinterconnect the pair of transversely disposed operating members 69 and74 as is best shown in Fig. 2. Thus, by

means of the nuts 1% and 107 the thrust members 56 and 57 may beelevated or lowered independently of each other.

From the description thus far it will be understood that the thrustmembers 56 and 57 are jointly adjustable during operation of therectifier simply by rotating the shaft '71. Rotation of the shaft 71 maybe by suitable manual means such as is indicated in Fig. 2 by thenumeral 112. After suitable adjustment of the rotatable member 112,which is integrally secured to the shaft 71, the member 112 may beafiixed in position by the locking bolt 113 as shown in Fig. 2. It willalso be understood that instead of the manual means 112, suitableautomatic means such as an electric motor, could be used to rotate theshaft 71 and that such a motor could be made responsive to the magnitudeof current being delivered by the rectifier or supplied thereto. In sucha construction it will be appreciated that the rectifier would be fullyautomatic and would respond to the magnitude of load current in such away as to adjust the dwell time of the contacts to accoma"! modatechanges in the magnitude of the load.

The modification of my invention as shown in Figs. 4, 5 and 6 isessentially like the arrangement shown in Figs. 1, 2 and 3 except thatthe arrangement of Figs. 4, 5 and 6 does not incorporate the ballmembers 54, 55, 58 and 59 shown in the modification of Figs. 1, 2 and 3and in addition the means for adjusting the thrust members, such as 56and 57, is different in the two modifications.

Furthermore, the arrangement of Figs. 4, 5 and 6 shows the bolting meansand 116 for respectively securing the D.-C. buses 4 and 5 in positionand the bolting means 117 and 11% for securing the alternating currentbus structures in position.

In order to support the thrust adjusting regulating means in themodification of Figs. 4, 5 and 6 plate members 119 and 12B arerespectively secured to the top of the unit by the bolts 121 and 122,and a horizontally disposed cross piece 123 is secured to the uprights119 and 12% by means of the bolts 124.

As in the modification of Figs. 1, 2 and 3 the arrangement of Figs. 4, 5and 6 is constructed so that each thrust member, such as 56 and 57 maybe adjusted individually through adjusting screws 125 which are lockedin position by the lock nuts 126. The adjusting screws 125 are mountedin the adjusting plate 127 so that when plate 127 is moved verticallyall the tapered thrust transmitting members such as 56 and 57 are movedin unison. In order to insure that each of the thrust transmittingmembers will move the same amount it is necessary to insure that theadjusting plate 127 is movable in the vertical direction without anywobbling effect. In order to prevent wobbling of the adjusting plate 127the vertically disposed elements 129 are rigidly secured in position tothe top plate 123 by means of the nuts 130 and are screwed into thesupport structure at their lower extremities as indicated at 131.Mounted about and slidable along each of the members 129 is a sleevemember 132 which, in turn, is affixed to the adjusting plate 127. Thus,it will be understood that by the sleeves 132 cooperating with thevertically disposed guide rods 129, the adjusting plate 127' isprevented from wobbling.

Vertical adjusting motion of the adjusting plate 127 is imparted bymeans of the rotatable adjusting bolt 133 which threadedly engages asleeve member 134 rigidly secured in position in an opening in theadjusting plate 127. Vertical motion of the adjusting bolt 133 isprevented by the collar assembly comprising the collar memher 135 whichis secured against vertical movement by the clamping ring 136 and theupper plate member 123 and due to engagement of the collar member 135with the portion 137 of the adjusting bolt 133. As will be seen in Figs.5 and 6, the adjusting bolt 133 is provided at its upper extremity witha suitable construction 138 such as a hexagonal periphery forcooperation with a suitable adjusting wrench to be operated manually.

From the description thus far it will be understood that rotation of thevertical adjusting member 133 as by a wrench will result in verticalmovement of the adjusting plate 127 which, in turn, will impart verticalmotion to the tapered thrust transmitting elements 56 and 57 and therebywill control the dwell time of the contacts of the rectifier. It willalso be understood that instead of a manually operable wrench as a meansfor driving the adjustable bolt member 133 such element could be rotatedby motor means which, in turn, could be responsive to the magnitude ofdirect or alternating currrent through the mechanical rectifier and insuch a way the rectifier would be automatically adjustable duringoperation insofar as the contact dwell time is concerned in response tovariations in the magnitude of the load current.

While I have shown and described particular embodiments of theinvention, I do not wish to be limited thereto and intend in theappended claims to cover all such changes and modifications as fallwithin the true spirit and scope of the invention.

I claim:

1. In combination, a rectilinearly movable switch member having a pairof spaced apart fixed contacts bridged thereby, a revolving cam memberhaving its axis spaced on the opposite side of the fixed contacts fromsaid switch member, means biasing said switch member to move toward saidcam member into engagement with the fixed contacts, and thrust meansincluding a reciproeating contact operating member having one endextending between the stationary contacts and an adjustable oscillatoryelement interposed between the other end thereof and said cam member forcausing said switch member to open during a variable part of eachrevolution of said cam member, said oscillatory element having a fulcrumadjustable relative to the axis of the cam member for shifting thereciprocating range of the contact operating member so that adjustmentof said fulcrum inversely varies the switch opening and closing parts ofeach revolution of said cam member.

2. In combination, a rectilinearly movable switch contact having a pairof spaced apart fixed contacts bridged thereby, a revolving cam memberhaving its axis spaced on the opposite side of the fixed contacts fromsaid movable switch contact, means biasing said movable switch contactto move toward said cam member into bridging engagement with the fixedcontacts, thrust means including a reciprocatory member having one endengageable through the space between the stationary contacts with saidbridging switch contact and an adjustable oscillatory element interposedbetween the other end thereof and said cam member for disengaging saidmovable switch contact from said fixed contacts during a variable partof each revolution of said cam member, means biasing said reciprocatorymember to move out of engagement with said bridging switch contact andinto engagement with said oscillatory element, and said oscillatoryelement having a fulcrum adjustable relative to the axis of said cammember for shifting the reciprocating range of said reciprocating memberto inversely vary the switch contact opening and closing parts of eachrevolution of the cam member.

3. In combination, a reciprocating electric switch contact having twospaced apart fixed contacts bridged thereby, means biasing thereciprocating contact into bridging engagement with the fixed contactsan aligned reciprocatory member operable through the space between thefixed contacts to disengage the reciprocating contact from the fixedcontacts, a cam member revolving at constant speed and having its axisdisposed in line with the reciprocating path of the reciprocatorymember, means biasing the reciprocatory member to move out of engagementwith the reciprocating switch contact and toward the cam member and atapered oscillatory wedging member interposed between said cam andreciprocatory members and having pivotal mounting means at one endthereof adjustable transverse the direction of reciprocation of the con-7 tact engaging member for shifting the range of reciprocation thereofto inversely vary the opening and closing parts of each revolution ofsaid cam member.

4. Cyclic mechanism having in combination a movable contact havingspaced apart stationary contacts in cooperating circuit controllingrelation therewith, means biasing the movable contact into bridgingengagement with the stationary contacts and a revolving cam memberhaving a cam follower assembly for opening the bridging contact during avariable part of each revolution of the cam member and including anoscillating member engaging the cam member and a reciprocating push rodhaving one end biased into engagement with the oscillating member andthe other end insulated and extending between the stationary contactsfor engaging the bridging contact to effect opening thereof, saidoscillating member having an adjustable fulcrum for shifting thereciprocating range of the push rod to inversely vary the contactopening and closing parts of each revolution of the cam member.

5. A periodic circuit opening and closing switch mechanism having incombination, a pair of spaced apart fixed contacts, a rectiiinearlymovable bridging contact therefor having means biasing the bridgingcontact intocircuit closing engagement with the fixed contacts, arevolving cam having means operated thereby including a push rodreciprocated between the fixed contacts into engagement with thebridging contact for periodically disengaging the bridging contact fromthe fixed contacts, and means including a pivoted oscillating elementinterposed between the revolving cam and the push rod and provided withan adjustable pivot for shifting the reciprocating range of the push rodto inversely vary the bridging contact circuit opening and closingperiods upon adjustment of said pivot.

6. In combination, a switch mechanism comprising .a pair of fixedcontacts in spaced apart alignment and a rectilinearly movable bridgingcontact therefor having spring means engaging one side of the bridgingcontact for biasing the bridging contact into circuit closing engagementwith the fixed contacts, a revolving cam having means operated therebyincluding a push rod reciprocated between the fixed contacts intoengagement with the other side of the bridging contact for periodicallydisengaging the bridging contact from the fixed contacts, and meansincluding a pivoted oscillating element interposed between the revolvingcam and the push rod and provided with an adjustable pivot for shiftingthe reciprocating range of the push rod to inversely vary the bridgingcontact circuit opening and closing periods upon adjustment of saidpivot.

7. A periodic circuit opening and closing switch mechanism having incombination, a pair of spaced apart fixed contacts, a rectilinearlymovable bridging contact therefor having spring means biasing thebridging contact into circuit closing engagement with the fixedcontacts, a revolving earn having an axially aligned push rodreciprocated thereby between the fixed contacts into engagement with thebridging contact for periodically disengaging the bridging contact fromthe fixed contacts, and means including a tapered oscillating elementinterposed between the revolving cam and the reciprocating push rod andprovided with a pivot adjustable transverse the direction ofreciprocation of the push rod for shifting the reciprocating range ofthe push rod to inversely vary the bridging contact circuit opening andclosing periods upon adjustment of said pivot.

References Cited in the file of this patent UNITED STATES PATENTS1,480,546 Cummiskey Jan. 15, 1924 1,812,647 French June 30, 19312,375,416 Huber May 8, 194-5 2,490,523 Kneisley Dec. 6, 1949 2,556,716Viol June 12, 1951

